The present invention relates to an arrangement for the sealed lead-through of at least one conductor through the wall of a housing.
More particularly, it relates to an arrangement in which at least one conductor is led through a housing which encloses a first medium, into a region which has a second medium, and a housing aperture closed by a closing part with a seal arranged between the closing part and the housing wall which surrounds the housing aperture.
Such an arrangement is known from DE-OS 28 45 139, in which a fuel filled interior of a fuel injection pump is provided with electrical control units, angle, and route transmitters, the connections of which lead from the fuel filled interior to a control device. The connections of the electrical components are taken to a breakthrough in the wall of the fuel injection pump housing, with the breakthrough being closed by a closing plate which is pressed tightly onto a ring seal supported in the housing. The connections of the structural components are routed outwards through holes in this seal plate to the pins of a plug-type connector. Sealing of the breakthrough and fixing is by means of soldering or embedding in a casting compound in the holes of the intermediate plate. This arrangement is rather elaborate and difficult to handle during assembly. While in the state of technology, the electrical components are accommodated in a fixed location, a further difficulty results if a component is accommodated as a movable item. It is then no longer possible to use rigid conductor connections from the connection point on the closure plate. A further disadvantage is that all contact points both between the electrical component and the conductor which leads away, and the conductor of the connection to the external plug pins, are exposed to the fuel.
Accordingly, it is an object of the present invention to provide an arrangement of the above-mentioned general type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in an arrangement in which the conductor is routed through a space between the closing part and the housing wall and is in close contact with the seal, at the very latest, in the closing position of the closing part.
When the arrangement is designed in accordance with the present invention it has the advantage that only a portion of the conductor connections is arranged within the fuel filled space and that the conductors) is/are routed to the outside through the separating point between the housing aperture and the closure part. This makes a separate fluid-tight connection between the internally arranged conductor and one outside the housing which leads away, to a plug, or to the connection of an electrical device, a control unit, or a circuit part, obsolete. With the use of the seal on the closure part, the lead-through point of the conductor(s) is tightly enclosed, sealing the housing at the same time.
In accordance with another feature of the present invention, two seals are arranged between the housing wall and the closing part and the conductor is routed through between the seals. This construction provides an improvement of the seal. In accordance with another feature of the present invention, the seal is a shaped seal which can be placed in recesses of the adjacent sides of the housing wall or a closing part. Here the sealing element or the sealing compound can be applied to the conductor with particular advantage. In accordance with a further feature of the present invention, the conductor is configurated as one entity from a conductor track which is pressure-tightly connected with a conductor track carrier and insulated against the outside. In a particularly advantageous manner, this contributes to the solution of the problem of a simple tight lead-through of conductors through the wall of a housing. The conductor carrier is advantageously clamped between the closure part and the housing, and does not form a bulky arrangement at the lead-through point by virtue of the fact that the conductor is designed in the form of flat copper tracks, so that high safety sealing against significant pressure differences between a medium inside the housing and a medium outside the housing, is ensured. The medium may be of different types, for example, liquid on one side and gaseous on the other side, or they may be of the same type, with one medium being in a physical state which differs from that of the other medium. With a sturdy design of the conductor track support or under light pressures, the conductor track carrier itself may form the closure part. However, in this advantageous arrangement, the conductor track support is an elastic carrier film, preferably polyamide, which supports the conductor tracks, and these in turn may be covered by an elastic cover film. The carrier film advantageously forms, a movable connection to the movable electrical components inside the housing.
The carrier film can be advantageously arranged on a carrier plate which supports the carrier film, or the carrier film may be provided on its own, if it is not exposed to large mechanical forces. To improve the tight lead-through, the carrier film may be routed through a seal, or, sealing materials may be applied to the carrier film. In this case, the carrier film can be used on its own, without any carrier plate. Together with the applied sealing compound, it forms a uniformly handling item which is easy to mount. A further feature of the present invention is that in the adherence region of the closing part to the housing wall, the carrier film has an all-round ring connected in particular on both sides with a seal, with an extension of the ring on each side carrying the conductor track leading from this ring to the interior of the housing and to the outside. This design results in a ring, having, for example, sealing material on both sides, which is then placed between the closing part and the housing wall and the otherwise provided shaped seal between the closing part and the housing wall. A carrier film strip or tail extends to the pump interior to provide a flexible contact with a movable electrical component, and to the outside the carrier film extends with a prolongation to make contact with other electrical components, such as an electrical control unit. Together with the coated carrier film, a component of the same thickness is inserted in the vicinity of the seal between the closure part and the housing, ensuring optimum seals.
The embodiments in accordance with the invention are of particular advantage when used in fuel injection pumps. However, there are many other applications wherever it is important to provide a simple and easily assembled lead-out of conductors from housings which need to be kept tightly sealed.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.